Technical Field
This disclosure relates to a light-emitting device.
Description of the Related Art
A light-emitting device known in the art may include a blue light-emitting diode (LED) in combination with a green light-emitting fluorescent material and a red light-emitting fluorescent material excited by the blue light to emit white-based mixed light. A light-emitting device included in an image display device, such as a liquid crystal display, is required to have a high luminous flux and reproduce colors in a wide range of chromaticity coordinates. The evaluation standard for color reproducibility is, for example, National Television System Committee (NTSC) ratio standardized by NTSC.
For example, Japanese Patent Application Publication No. 2008-303331 describes a light-emitting device for use in a liquid crystal display that is required to have a color reproducibility of 95% or more in NTSC ratio. The light-emitting device includes a light-emitting element having a peak emission wavelength in a range of from 390 nm to 550 nm, a green light-emitting β sialon fluorescent material, and a red light-emitting fluorescent material represented, for example, by CaAlSiN3:Eu.